In this proposal, we explore host innovation through alternative splicing of antiviral genes altering their localization and activity to neutralize the virus. The host remodels its gene expression program to neutralize viral infection, while the virus antagonizes antiviral genes, making this a hotspot for host-pathogen interactions. One strategy that pathogens utilize to evade host detection is by hiding in compartments that are not under surveillance by viral restriction factors or pathogen recognition receptors. In this proposal, we explore host innovation through alternative splicing of antiviral genes altering their localization, and activity to neutralize the virus. We have identified key antiviral genes that produce alternatively spliced gene products that have gained new modifications to traffic and guard distinct sites that are essential for the viral lifecycle. Alternative splicing of a gene can lead to the modification of protein structure and function. One such modification of interest in this study is prenylation of antiviral genes. Prenylation is an important post-translational modification that targets proteins to membranes of the organelles. Prenylated proteins are hydrophobic, associate with lipid binding proteins, and are generally targeted to membranous subcellular compartments. However, less understood is the role of protein prenylation in antiviral immunity. We hypothesize the host has evolved to counter RNA viruses by driving prenylated antiviral proteins to distinct subcellular compartments placing proteins in proximity to viral machinery. Generation of membrane-targeted antiviral proteins through alternative splicing is the host adaptation to infiltrate these viral sanctuaries and restrict viral replication, assembly and/or trigger innate immune responses. This proposal will provide insights into: i) If membrane targeting augments the activities of antiviral proteins? ii) Is alternative splicing an evolutionary adaptation due to pathogen pressure? and iii) Does the localization of the antiviral protein determine the type of virus it can restrict? This work will provide novel insights into cell-intrinsic antiviral countermeasures, new antiviral drug targets, and alternative splicing as a novel interface for host-virus interactions.